Zed Head

Your problem is pretty common and probably easy to solve. But you'll have to give more details if you want more specific ideas. On the other hand, it is fun to test all of the many possible causes. Fuel pump, fuel filter, gas quality, injectors, ECU signal wire from coil, vacuum leaks, EGR system, relays, etc. A lot of high quality garage time there. Good luck.

What's on the rag? Gasoline? "Aerosol" means it's in the air. Weird that somebody chose "soaked rag" to mean aerosol. You're describing some sort of procedure but the words don't fit. No offense. There's no "ignition pack" on a ZX. Did it run for 10 minutes after you took the rag off or did it run for ten minutes with the rag on, then died when you took the rag off? Still no details on how long you've had the car, and if it ran before you got it. Might just be that there's very old gasoline in the tank. Old gas causes problems.

Try turning the engine off then pulling the hose. Just to see if it's wetter, the engine vacuum won't pull through the hose with the engine off so any leakage should still be there. The fact that it runs better when you turn the pump off is a sign that it wants a leaner mixture though. Seems like you need a new FPR. Edit - if the FPR is leaking you might see some drops at the hose nipple for the vacuum source, on the FPR itself. Run the fuel pump with the vacuum hose off.

What does "take the rag off" mean? What happened when you tried to start it again after it ran for 10 minutes? Does it restart with "aerosol"? Seems like you almost have the problem solved already. You need to supply a lot more details, like if the car was supposed to run when you got it, or if it sat for a long time.

It wouldn't be a vacuum leak, but you'd be sucking fuel straight through the FPR. Vacuum on one side of the diaphragm, fuel on the other. It's a flexible fabric that gets old and cracks. A small crack can let a lot of unmetered fuel into the intake manifold. Not uncommon.

Check the vacuum hose to the FPR for raw fuel. Could be a hole in the diaphragm.

Are you sure it's not a grinding wheel bearing? Chunks of bearing. How does it sound if you get the wheel off the ground, put the trans in neutral and spin the wheel?

I think that the EFI system engines always sound like they have a miss at idle. Because all 6 injectors open at the same time and each cylinder is at a different point in it's 4 cycles. They don't all get the same type of fuel-air charge. I think that it leads to incomplete combustion in some cylinders and that's why the manufacturers developed sequential injection for idle and low RPM. You'll know more when the engine is under load. Good luck.

Does the engine stumble or lag when it backfires? Some people call it "frontfire". Sounds a bit like the "lean" problem that many of us have fixed by adding a potentiometer in to the coolant temperature sensor circuit. http://www.atlanticz.ca/zclub/techtips/tempsensorpot/index.html

https://www.monroe.com.au/trade-corner/tech-info/gas-charging/gas-charged-shocks-struts-replacement-cartridges.html

What was in gundee's secret PM?

The gas in the strut is not for lifting. Not sure what you mean by "spring/pressure", there's no spring inside the shock. The gas charge should be the same across platforms, it's just there for sealing and/or foam reduction. Might be that you got a defective over-pressurized strut/shock. Tokico, the company, has been in limbo for many years, wouldn't be a surprise if there were counterfeits or bad stock out there. Get some reasonably priced KYB's and you'll probably be very happy, with no problems. Here's an old thread about the part numbers. Good luck. https://www.zcar.com/forum/10-70-83-tech-discussion-forum/277489-strut-interchangeability-now-can-told.html

Can you pop the cover off of the old one and look for carnage? Magnet shavings, chipped gears, ovaled holes? That would finish the story. We need more destruction pictures for diff problems.

This measurement is the one that determines gear "play", and describes how to adjust it.

Is it a reman? How old? Might just be bad bearings in the alternator. The voltage numbers look good. If it's a reman it probably has a lifetime warranty. Go get another one and hope.

John C and others have said that the old open R180's are susceptible to one wheel burnout failure. The seat for the pinion shafts gets wallowed out.

All of the joints are visible for where you're twisting. See which parts move and which parts. Grab both sides with each hand and twist. The video sounds "grindy".

BZ3038 is the base shock, the others are renumbered based on the gland nut or the space underneath. They're the same shock just different part numbers based on the accessories. I have some of the basic Tokicos in the garage with both labels. I can peel one off and 3038 is underneath. Your problem would be with how long the shock is when compressed. The strut is not settling under the weight of the car. Have you run them through the travel? Maybe they're binding up. You should be able to fully compress the shock by hand.

The fluid passes right through it. Front and back are separated. The piston in the middle moves if there's a pressure differential.

If you can remove the spring and run the strut through its travel you'll know if it's binding or not. It does seem like your spring is incorrectly seated though. The bearing sits in a pocket, if it wasn't seated properly it would move the spring seat downward relative to the body mounting point. Good luck.

Motorsport and ZCar Depot are good starting points. I have a combination switch if you want to go back to the factory light setup. Somebody probably has some window cranks to replace the vise-grips. https://www.classiczcars.com/forums/forum/93-vendor-marketplace/

This bushing has a long side and a short side. Maybe installing backward can cause things to bind up. If so, you can just swap arms, no need to swap bushings.

Here's a 72 image from Hagerty. https://www.hagerty.com/articles-videos/articles/2018/09/20/datsun-240z-values-show-appreciation

Oops, I didn't scroll up far enough. You can reach the suspension bolts from the side when the car is on the ground. Loosen them up a bit and roll the car back and forth. No danger if the car isn't being driven. Your front end is way up there though. That's probably why your wheels are carked.

Your front end looks very high, like you have high rate springs on the front struts. The wheels will pull in at the bottom as the body and wheels get farther apart. You might be describing the secondary effect of the car not settling at all, due to some other problem. Any chance you got your springs mixed up front to back? Take a picture from the side and post it.